PURPOSE: To enhance the strength and voltage withstand property of an insulator as well productivity of an ignition plug by sintering a heater independently of an insulator, and providing the heater on a tubular heater element mounted on the surface of a long leg portion.
CONSTITUTION: A heater element 10 in which a heater 14 is mounted is formed by sintering independently of an insulator 3 and is then mounted to the long leg portion 8 side of the insulator 3 formed by sintering independently of the heater element 10. As a result, productivity of the insulator 3 becomes excellent. Since the insulator 3 is sintered while not having the heater 14, the insulator 3 can be sintered at high temperatures as is a normal ignition plug not having the heater 14. As a result, the strength and voltage withstand property of the insulator 3 are heightened as compared with conventional insulators sintered simultaneously with heaters. Furthermore, mounting of the sintered heater element 10 to the sintered insulator 3 reduces the probability that the insulator is cracked or damaged when the heater element 10 is mounted thereto.
MATSUMURA SHUZO
MATSUBARA YOSHIHIRO
